Why is 5k the standard for conventional?

[doublebase]

Originally Posted By: HTSS_TR
Originally Posted By: doublebase
Originally Posted By: HTSS_TR
My 1994 Lexus LS400 recommended 7.5k for dino 5W30. 5k wasn't the standard for conventional oil ever, some manufactures may recommend 5k but not all.


What? Where does it say that in the owner's manual? I own a LS460 and the recommended oil changing interval is 5,000 miles.

Your LS460 is fairly new, after 2005-2006 right ?

I am talking about 1994 LS400, I sold the car few months ago, otherwise I could make a copy of the maintenance page and post it here.

One think I forgot to mention was 7500 miles was for non-severe driving condition.

This is post on a Lexus club:

Quote:
Directly from my 1999 Owners Manual Supplement:

"OIL CHANGE INTERVALS - The maintenance schedule log book has been designed to provide you with the flexibility to allow either 5,000 or 7,500 mile oil change intervals depending on your circumstances.

Use 5,000 mile oil change intervals to help ensure proper engine lubrication under most driving conditions or if you primarily operate your Lexus under the "special operating conditions" described on page 70.

Use 7,500 mile oil change intervals if you primarily operate your Lexus under light, non commercial duty for distances greater than 5 miles in temperate climates (above freezing and below 90)."


http://us.lexusownersclub.com/forums/topic/54033-oil-change-interval/


Wow that's nuts...I'd consider those intervals a little bit ahead of the times. Now everyone is doing it, but I didn't realize the LS400 was doing it back then. My car is an 07, the interval is supposed to be 5,000 miles. Lexus has changed their newer vehicles to 10,000 miles intervals using 0w20 Toyota full synthetic. Supposedly I can also do the 10,000 mile service interval on a synthetic, but I talked to a shop foreman at a local Lexus dealer and he said he'd stick to 5,000 mile intervals. I think that's a little too short with a high quality synthetic, so occasionally I extend it out to 7,500 miles depending on if I'm using any oil between changes, the type of driving I'm doing, etc.

 

[camrydriver111]

Originally Posted By: Pontual
It started with 500 miles oci in the 20's, 2k miles i the 50's 3k in the 60's and 70's. 5k in the 90's and now ?


I think this is probably the case.

It has to be the oil change culture rather than oil technology since some manufacturers break from the trend, and have previously done so with API SH oil.

My opinion right now is that 5k is the new 3k.

 

[puredata]

My mechanic put a sticker on my car for 3k oil change. The oil I brought him was Pennzoil Ultra Platinum 0w20. I warned him and he put a sticker for 5k.

I gotta find the location of my oil filter eventually. This thing is getting expensive to have it changed by mechanic.

 

[Merkava_4]

Originally Posted By: Yup
I'd run it 7500 or 6-8 months whichever comes first.


That tells me you don't care very much for your car.

 

[Ifixyawata]

Originally Posted By: Merkava_4
Originally Posted By: Yup
I'd run it 7500 or 6-8 months whichever comes first.


That tells me you don't care very much for your car.


The fact that he changes it at all says he (like all of us on here) cares a great deal more than your average car owner who doesn't even know what oil their car takes and even some who probably don't know the last time it was changed.

 

[WobblyElvis]

Originally Posted By: Merkava_4
Originally Posted By: Yup
I'd run it 7500 or 6-8 months whichever comes first.


That tells me you don't care very much for your car.


Nothing wrong with Yup's opinion. I agree.

 

[BrocLuno]

Back in the late 1980's the State of California Fleet Administration (which runs the State Garages, the loaner fleet, and the rule book for departmental cars and light trucks) ran a whole series of tests. They did UOA's and engine wear analysis, transmission fluid analysis, and got inputs from the OEM engineers.

They finally determined that the optimum for value and longevity was 6,000 mile oil changes and filters every other time. This is for a fleet of some 50,000 vehicles of all makes and models.

So when you are issued a vehicle by the State, it will come with it's own maintenance log book. And it gives all the requirements for normal maintenance. All the garages in the State that are certified to work on state vehicles have the same guidelines. Everyone plays by this book, and has for now three decades.

This all started when there were only dino oils readily available. And even the Calif Hyway Patrol cruisers never saw a qt of synthetic anything except maybe brake fluid. So the real "norm" is 6,000 - not 5,000.

What your local mechanic or lube shop does for marketing is one thing. But actual high volume fleet management has not been using 5K for a long time ...

And the cars and trucks in this program all go over 150,000 before they get looked at for auction potential. If the fleet inspectors think they can go longer, they do...

My last truck (V6 Ford Ranger 4x4) that saw a LOT of off road use in tough situations went 253,000 plus before it went to auction running just fine. I did get an OK to move it to HDEO (15W-40) because of the amount of off-roading it had to do in the desert in the summer in hot conditions.

The program works and there are now hundreds of thousands of cars and trucks to prove it ...

 

[BrocLuno]

And by the way, dino oil can go longer than 7,500. There are fleet trucks running just HD Dino oils that regularly go 15,000 miles between changes. Yes they have multiple filters, but the oil does just fine. So the idea of doing OCI's at any mileage is just an idea. UOA's are the way to make sure.

But then other maintenance does not get performed regularly like brake inspections, light inspections, tire wear inspections, etc. So the car maintenance industry has tried to settle on a number they can teach the public to have their cars "looked after". 5K is a convenient number that's easy for Joe Blow to remember

 

[MuzzleFlash40]

Even in the Wife's direct injection engine the semi-syn had plenty of life left at 5k when it was checked. When I run out of oil changes from the dealer for $10 a piece at around 100k miles I'll switch to a synthetic, and start doing it at 7.5k which is Hyundai's maximum OCI allowed.

 

[SR5]

Originally Posted By: BrocLuno
State of California Fleet Administration ...

They finally determined that the optimum for value and longevity was 6,000 mile oil changes and filters every other time. This is for a fleet of some 50,000 vehicles of all makes and models.

This all started when there were only dino


Good info BrocLuno.

The rule of thumb in Australia is every 10,000km (=6200 miles)

 

[RoadRaceJosh]

My Nissan warranty stipulates 5k mile oil changes so that's what it's getting until the warranty expires at 30k. UOA has shown that the oil is serviceable well past 5k. I have 23k on the truck now. At 25k I'll change the oil, use synthetic and run it 7500 miles and repeat that for the foreseeable future. I have little doubt that 10k mile changes with synthetic would be fine, but with materials costing me $15 per oil change (clearance Wix filters and on-sale/rebate eligible synthetic) and UOA costing $25 I'm happy to change the oil.

 

[FCD]

6k miles or 12 months for my 1975 Ford Capri on 10w40, 20w40 or 20w50 dino.

 

[Gene K]

Even Direct Injection Gas Turbos seem to be able to go 5000 miles on today's conventional.

VW Turbo, 3.0 Sludger Toyotas, and 2.7L Mopars are the only engines I can think of that might not.

 

[bulwnkl]

5k miles is super-easy to remember. Nothing more to it than that.

 

[Bgallagher]

Go with whatever the manufacturer recommends. OLM or what is in the manual.

 

[Nickdfresh]

Originally Posted By: Merkava_4
A 5 quart bottle of Chevron Supreme is only $11.77 at Walmart. There's no reason to run that out to 5K unless you got some serious financial issues.


Or you could just change your Model T every 500 miles to be extra extra safe!

 

[Merkava_4]

Originally Posted By: Nickdfresh
Or you could just change your Model T every 500 miles to be extra extra safe!


Are you saying that Chevron Supreme SN GF5 is as antiquated as a Model T ?

It's got state-of-the-art ISOSYN technology! Says so right on the bottle!

 

[Garak]

Merk, you're our very own Jack Benny with a Maxwell.

 

[fdcg27]

It isn't.
GM recommended 6K drains forty years ago (I have a 1974 OM) and Honda recommended 7.5K for years before they put IOLM monitors in their cars.
We also have a mod here who ran 15K on bottom dollar conventional with nothing ill to show from it in a UOA.
Everything will depend upon how the engine is used.
Use one as I do and the thing runs twenty five miles twice a day five days a week, so oil life should be long.
Use one as my mother does and shorter drains are probably in order.
The notion that 5K is somehow the right drain interval for conventional is simply wrong.
For drivers who'll never check the oil level and add a quart if needed, even 5K might be too long, though.
This probably factors into a lot of shop OCI recommendation since they probably see many engines coming in very low on oil with drivers clueless about when the oil was last changed.
For a lot of owners, 5K is probably 5K plus three months.
Not too much of the driving world operates on BITOG obsessiveness although we do of course.

 

[SR5]

Originally Posted By: fdcg27

Not too much of the driving world operates on BITOG obsessiveness


So true. I work with scientists, engineers and machinists. All are well educated and drive cars, some are interested in oil, however most are not. Very few could tell me what oil is in their car. Most just go to the dealer / local mechanic when their windscreen sticker says it's time.